Cytotoxic chalcones and antioxidants from the fruits of Syzygium samarangense (Wax Jambu)

Bioassay-guided fractionation of the methanolic extracts of the pulp and seeds of the fruits of Syzygium samarangense (Blume) Merr. and L.M. Perry led to the identification of four cytotoxic compounds and eight antioxidants on the basis of HPLC-PDA analysis, MS, and various NMR spectroscopic techniques. Three C-methylated chalcones, 2′,4′-dihydroxy-3′,5′-dimethyl-6′-methoxychalcone (1), 2′,4′-dihydroxy-3′-methyl-6′-methoxychalcone (stercurensin, 2), and 2′,4′-dihydroxy-6′-methoxychalcone (cardamonin, 3), were isolated and displayed cytotoxic activity (IC50 = 10, 35, and 35 μM, respectively) against the SW-480 human colon cancer cell line. Also a number of known antioxidants were obtained including six quercetin glycosides: reynoutrin (4), hyperin (5), myricitrin (6), quercitrin (7), quercetin (9), and guaijaverin (10), one flavanone: (S)-pinocembrin (8), and two phenolic acids: gallic acid (11) and ellagic acid (12).